Barca's 3-1 loss leaves Madrid on top

BARCELONA, Spain -- Four days after affirming its European credentials by toppling Manchester City, Barcelona slumped to a stinging 3-1 loss at Real Sociedad to relinquish the provisional Spanish league lead to Real Madrid on Saturday.

Gareth Bale scored a blistering long-range strike to help Madrid brush aside Elche 3-0 at home, and Barcelona was unable to match that with a win. Instead, it was overrun by Sociedad's dynamic attack led by forwards Antoine Griezmann and Carlos Vela.

Barcelona's defeat confirmed the change in course in the league title race over the past two months, leaving Madrid in command and waiting to see if Atletico can keep up when it visits Osasuna on Sunday. After starting the season with 13 wins and a draw, Barcelona has dropped points in four of its last seven games.

Barcelona coach Gerard Martino shuffled his lineup from Tuesday's Champions League victory at City and tried to reinforce his defense by playing with two holding midfielders in Sergio Busquets and Alex Song.

The move backfired when Song scored an own goal in the 32nd minute in the first of several defensive lapses that doomed the defending champions.

Lionel Messi equalized in the 36th, only for Griezmann to restore the hosts' advantage after an error by defender Marc Bartra in the 54th before setting up David Zurutuza in the 59th.

The loss left Barcelona three points behind Madrid, the first time it has trailed its fierce rival this season. Atletico is also three points behind Madrid before it plays on Sunday.

The last time Barcelona lost by more than one goal was a 3-0 defeat to Bayern Munich in May 2013.

Martino took the blame for the humbling defeat.

“Real (Sociedad) deserved to win,” he said. “I didn't make the correct reading of the game. The decision not to change was also a mistake.”